Chiral glycerol derivatives

Abstract

Enantiomerically pure glycerol derivatives, e.g. S-1,2-O-isopropylidene, S-1,2-O-benzylidene, and R-1,2-O-dibenzyl glycerol, have been prepared from 1,2R-O-protected erythritols in high yields. The latter compounds are easily obtained from erythorbic acid and are useful building blocks in the synthesis of a host of optically active compounds having biological activity.

What is claimed is: 
     
       1. A process for preparing an enantiomerically pure 2-deoxy pentofuranose selected from the group consisting of 2-deoxy-L-xylose, 2-deoxy-L-ribose, 2-deoxy-D-xylose and 2-deoxy-D-ribose, which comprises: (a) selecting 4,5-O-arylidine-3-O-protected 3,4,5-trihydroxy pentane derivatives of the Formulae ##STR1## wherein Ar and R are each an O-protecting group wherein Ar is an aromatic or a substituted aromatic selected from the group consisting of aryl; alkaryl; o-, m- or p-tolyl; o-, m- or p-methoxyphenyl; o-, m- or p-chlorophenyl; or alpha- or beta-naphthyl, the substituents selected from the group consisting of 1-3 lower alkyl groups, 1-3 lower alkoxy groups or 1-3 halogen atoms and R is selected from the group consisting of an aliphatic, cycloaliphatic, alkaryl or silyl; wherein the aliphatic or cycloaliphatic is preferably of up to six carbon atoms;   b) reducing with an alkali metal borohydride the pentane derivative to form 3,5-di-O-protected-2-deoxy pentanofuranose having the same chirality as the pentane, of the Formulae ##STR2## separating by filtration a selected enantiomerically pure 2-deoxy pentofuranose; and   recovering by chromatographic elution said separated 2-deoxy pentofuranose.   
     
     
       2. The process of claim 1 wherein the aryl is selected from the group consisting of phenyl, naphthyl or substituted phenyl and the alkaryl is selected from alkylphenyl or substituted alkylphenyl; the substituents are selected from the group consisting of 1-3 lower alkyl groups, 1-3 lower alkoxy groups, or 1-3 halogen atoms.